Wavecrest OE-2 User manual

W
AVECREST Corporation
OE-2
Optical to Electrical Signal Converter
User’s Guide and Reference Manual
200005-01 REV A

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WAVECREST Corporation continually engages in research related to
product improvement. New material, production methods, and design
refinements are introduced into existing products without notice as a
routine expression of that philosophy. For this reason, any current
WAVECREST product may differ in some respect from its published
description but will always equal or exceed the original design
specifications unless otherwise stated.
Copyright 2002
WAVECREST Corporation
A Technologies Company
7626 Golden Triangle Drive
Eden Prairie, Minnesota 55344
[phone]
[phone]
www.wavecrest.com
All Rights Reserved
U.S. Patent Nos. 4,908,784 and 6,185,509, 6,194,925, 6,298,315 B1, 6,356,850
and 6,393,088; other United States and foreign patents pending.

ATTENTION: USE OF THE SOFTWARE IS SUBJECT TO THE WAVECREST SOFTWARE LICENSE TERMS
SET FORTH BELOW. USING THE SOFTWARE INDICATES YOUR ACCEPTANCE OF THESE LICENSE
TERMS. IF YOU DO NOT ACCEPT THESE LICENSE TERMS, YOU MUST RETURN THE SOFTWARE FOR A
FULL REFUND.
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agreement with Wavecrest.
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subject of certain patents pending. Your license confers no title or ownership in the Software and is not a sale of any
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They are delivered and licensed as commercial computer software as defined in DFARS 252.227-7013 Oct 1988,
DFARS 252.211-7015 May 1991 or DFARS 252.227.7014 Jun 1995, as a commercial item as defined in FAR 2.101 (a),
or as restricted computer software as defined in FAR 52.227-19 Jun 1987 or any equivalent agency regulations or
contract clause, whichever is applicable.
You have only those rights provided for such Software and Documentation by the applicable FAR or DFARS clause or
the Wavecrest standard software agreement for the product.

OE-2™ User’s Guide and Reference Manual
Table of Contents
Preface Organization and Inspection...........................................................v
SECTION 1 Introduction......................................................................................1
Features..........................................................................................1
How the OE-2 Works......................................................................2
Laser Safety....................................................................................3
SECTION 2 Front and Back Panel Descriptions................................................5
Front Panel Controls and Connectors .............................................5
Back Panel Controls and Connectors..............................................7
SECTION 3 Instrument Set-up and Measurement.............................................9
Test System Requirements.............................................................9
Before Using the OE-2....................................................................9
Instrument Setup.............................................................................9
VISI™ Software Setup and Configuration......................................10
Manually Assigning GPIB Addresses............................................11
Automatically Assigning GPIB Addresses.....................................11
Setting Acquire Options.................................................................13
External Calibration.......................................................................15
Output Setting Options..................................................................16
Trigger Options..............................................................................17
View Options.................................................................................17
Taking a Measurement..................................................................18
Appendix A Specifications and Maintenance................................................19
Appendix B GPIB Commands.........................................................................23
Appendix C Preprogrammed Measurement Limits.......................................27
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iv

PREFACE
Organization
The manual is divided into three Sections and three Appendices. The following is a brief description of
the information contained in each section. For quick reference to specific information, refer to the Table
of Contents.
SECTION 1 — Introduction
This section introduces the user to the OE-2. Features and capabilities are described. An overview of the
internal operation of the OE-2 is also included.
SECTION 2 — Description
Describes the front and back panels of the OE-2.
SECTION 3 — Set-up and Measurement
Describes the installation and set-up of the OE-2 as well as using Virtual Instruments Signal Integrity™
software through a
WAVECREST SIA-3000 or DTS-207x instrument.
APPENDIX A — Specifications
This section contains a comprehensive set of specifications for the OE-2.
APPENDIX B — GPIB Commands
Includes various parameters, values and codes necessary for implementing remote control of the OE-2 via
the IEEE-488 interface.
APPENDIX C — Preprogrammed Measurement Limits
Includes a series of tables that show the preprogrammed measurement limits for each OE-2 model.
WARNING
Operating the OE-2 outside of the maximum operational specifications
published in Appendix A of this manual can damage the instrument.
The Wavecrest Warranty does not cover damage resulting from
improper operation or mishandling of the OE-2.
OE-2 Preface |
v

Inspection
If the contents are incomplete or damaged, contact WAVECREST Corporation Customer
Service: 1-800-733-7128.
 Inspect the shipping box for damage.
If the shipping box is damaged, or the cushioning materials show signs of stress, notify
the shipping carrier as well as the WAVECREST Corporation office. Keep the shipping
materials for the carrier’s inspection.
 Check for accessories.
 Power cord
 Two (2) build-out SMA connectors for Dual-channel instrument; one (1) connector
for Single-channel instruments
 Two (2) optical build-out connectors for Dual-channel instrument; one (1) connector
for Single-channel instruments
 OE-2 User’s Guide and Reference Manual
 Inspect the instrument.
If there is mechanical/physical damage, or if the instrument does not power up properly,
notify WAVECREST Corporation . Keep the shipping materials for the carrier’s
inspection.
WAVECREST Corporation will arrange for repair or replacement at their
option.
| OE-2 Preface
vi

SECTION 1– Introduction
The WAVECREST OE-2 converts optical communications signals into electrical signals. In
combination with a WAVECREST DTS or SIA system, the OE-2 enables accurate, high performance
jitter measurements on optical signals. The OE-2 can be operated in local mode or it can be
controlled through its GPIB interface using WAVECREST’s Virtual Instruments™ Signal Integrity
(VISI) software.
Features
The OE-2 incorporates all of the features needed for making single- or dual-channel, high
performance optical signal measurements.
Fully Calibrated - The OE-2 is fully calibrated from the optical input to the electrical output permitting
accurate signal level measurements without the need for additional instruments.
High Bandwidth - Enables measurement of high-speed data communication signals.
Built-in Amplifiers - Boosts low power signals to measurable levels.
Built-in Filters - Used to establish the noise bandwidth of optical signals. Available filter options include Fibre
Channel, Fibre Channel 2X, Gigabit Ethernet, InfiniBand™, XAUI, and SONET OC-48.
Power Meter - Each channel of the OE-2 includes an average optical power meter.
High-Speed Measurements -
WAVECREST DTS or SIA system with an OE-2 can quickly make highly
accurate jitter measurements.
GPIB Interface - The OE-2 can be run remotely via the GPIB or locally via the front panel.
Dual Channel Capability - The OE-2 is available in single-channel or dual-channel models.
Figure 1 – Dual-Channel OE-2 shown with WAVECREST SIA-3000
Section 1 | Introduction | 1

How the OE-2 Works
The OE-2 consists of a high-performance optical-to-electrical converter followed by wide-
bandwidth, signal processing devices. Dual-channel models incorporate two identical channels.
The block diagram below shows the structure of one OE-2 channel.
Figure 2 – Block diagram of an OE-2 channel
The optical input signal is converted to an electrical current using a low-noise, temperature-
stabilized photo receiver. The electrical signal is then amplified by a wideband transimpedance
amplifier (TIA) integrated within the photo receiver.
Because optical signals may have high levels of wideband noise, filters are often used to improve
the signal-to-noise ratio. Communications standards require a fourth-order Bessel-Thomson
low-pass filter characteristic with a cut-off frequency of 75% of the data rate. Each channel of
the OE-2 has four filters—for different communications protocols—selectable by electronic
switches. In addition, a fifth setting bypasses the filters for full-bandwidth operation.
Filter settings can be independently selected for each channel using front panel controls or
through the GPIB interface.
A bank of wideband electronic amplifiers follows the filters. These electronically switched
amplifiers amplify the electrical signal by approximately 10 dB, 20 dB, 30 dB or 40 dB. The
amplifier setting can be independently selected for each channel using front panel controls or
through the GPIB interface.
The average current in the photo receiver is measured to determine the average optical power of
the input signal and is available only through the GPIB interface.
The signal gain in every filter and amplifier path in the OE-2 is measured and stored locally in
the OE-2. These calibration values are used by
WAVECREST’s VISI software to display accurate
optical signal power levels.
A central processor controls all OE-2 functions. The processor also handles communication with
the GPIB interface port.
| Section 1 | Introduction
2

Laser Safety
Although the OE-2 optical to electrical converter does not emit laser energy, it does process
optical signals from laser devices. Therefore, laser signals will be present at the OE-2 inputs.
These signals present retinal and/or personal hazards because they are invisible and might not be
detected until injury to the eye or skin has occurred. To prevent injuries, basic precautions
should be followed.
• NEVER look directly into an optical signal connector. Always assume a laser beam is present.
• NEVER direct an optical output signal connector in a direction that could cause harm to
personnel nearby.
• Always turn optical output signal devices OFF when not in use.
• Where practical, protective eyewear that is designed for the signal wavelengths used should
be worn.
Section 1 | Introduction | 3

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| Section 1 | Introduction
4

SECTION 2 – Front and Back Panel Descriptions
This section describes the front and back controls and connectors of the OE-2.
Dual Channel OE-2 Front panel
Front Panel Controls and Connectors
Filter Selection
The OE-2 routes the converted signal through low-pass filters to establish a finite, repeatable measurement
bandwidth for the OE-2. Fourth-order Bessel-Thomson low pass filters are exclusively used.
3
1
4 56 7
2
9
8
1
The filter selection knob selects one of the four low pass filters or full bandwidth. Filter options are
described in Appendix A. Filters are independently selected for each channel; dual channel models
can use two different filters.
Filter selection can also be made through the GPIB interface. See Appendix B for GPIB commands.
2 Amplifier Selection
The amplifier selection knob selects one of the four amplifier settings. The gain is approximately 10dB
per amplifier.
• 10 dB
• 20 dB
• 30 dB
• 40 dB
Amplifier selection can also be made through the GPIB interface. See Appendix B for GPIB commands.
Section 2 | Front and Back Panel Descriptions | 5

3Over range LED/Signal LED
Two LEDs on the front of the OE-2 indicate optical input signal status. The lower “SIGNAL” LED is lit
when the OE-2 senses an optical signal. If the upper “OVERRANGE” LED is blinking red, the optical
signal power is beyond the input range of the instrument and should be removed to prevent damage to the
optical detector.
If both LEDs are blinking, the O/E receiver temperature stabilization is not within range. Measurements
made during this condition are not valid. If this occurs, turn off the unit for a few minutes and turn it back
on. It may be necessary to move the OE-2 to a cooler location. If this condition persists, the unit should
be serviced by an authorized
WAVECREST service representative.
4Channel 1 Optical Input
This FC/UPC input connector accepts either single-mode or multi-mode (up to 62.5 um) optical fibers.
Optical signals from 770 to 1650 nm can be used.
Before attaching any connector to the OE-2, clean all optical connections using an optical
fiber connector cleaner such as the NTT-ME CLETOP.
CAUTION: Do not exceed +3 dbm peak optical power.
5Channel 1 Electrical Output
The electrical output signal is available at this 50 Ohm SMA connector. The converted electrical signal is a
linear representation of the optical signal.
CAUTION: This output port is sensitive to electrostatic discharge. Use ESD protection when
connecting to this port.
6Channel 2 Optical Input
This FC/UPC input connector accepts either single-mode or multimode (up to 62.5 um) optical fibers.
Optical signals from 770 to 1650 nm can be used.
Before attaching any connector to the OE-2, clean all optical connections using an optical
fiber connector cleaner such as the NTT-ME CLETOP.
CAUTION: Do not exceed +3dbm peak optical power.
7Channel 2 Electrical Output
The electrical output signal is available at this 50 Ohm SMA connector. The converted electrical signal is a
linear representation of the optical signal.
CAUTION: This output port is sensitive to electrostatic discharge. Use ESD protection when
connecting to this port.
8Front Panel On/Off Switch
The front panel switch turns the internal power supply on or off.
9Local/Remote Switch
The Local/Remote switch selects between local mode and remote GPIB operation. In local mode,
settings are selected using the Filter and Amplifier Selection knobs. In GPIB remote operation, settings
are selected by using OE-2 -specific commands via the GPIB. Any operation/parameter change
performed at the SIA-3000™ will override the GPIB selected settings. The Local/Remote pushbutton
is lit when in local operation.
| Section 2 | Front and Back Panel Descriptions
6

Back Panel Controls and Connectors
12
10
14
13
11
15 16
OE-2 Back Panel
10 AC Input Port
IEC Inlet for AC cord. Connect to an AC source in the range of 100-240 VAC, 47-63 Hz.
11 Fuse
Primary AC fuse. Located inside of connector housing. Should be replaced with two Wickman
4AT/250V fuses (5x20 mm).
12 Reset Pushbutton
The Reset Pushbutton resets the OE-2 to the Power-Up state. This state is set to Full Bandwidth, 10DB,
1550NM in the factory. The end user may change this setting remotely by using GPIB commands that
are specified in Appendix B.
13 Fan Exhaust
Exhaust port for internal cooling fan. Maintain at least 1-inch (2.5 cm) clearance.
14 AC Primary Switch
Controls the AC mains to the instrument.
Section 2 | Front and Back Panel Descriptions | 7

15 GPIB Input Connector
Connector for GPIB cable. Used for controlling the OE-2 with a computer or other instrument. A GPIB
device address can be set using the 32-position DIP switch (see below), with address 0 reserved for the
controller and the remainder of the settings available at the user’s discretion. A full GPIB command set is
provided in Section 3.
16 GPIB Port Address Switch
Sets the address of the GPIB port. The address can be set from 1 to 31. Address 0 is reserved for the
controller; the default OE-2 address is 6.
The switch settings are in binary format as shown in the drawing below. For example, the switch setting
shown below selects port 6. The last three switches are not used.
IEEE-488 Port Address Not Used
0
1
LSBMSB
| Section 2 | Front and Back Panel Descriptions
8

SECTION 3 – Setup and Measurement
This section describes the set-up of the OE-2 and provides instructions that enable the user to
take a quick measurement for rapid familiarization with the instrument.
In addition, this section describes the Virtual Instrument Signal Integrity™ (VISI) software tools
necessary for using the OE-2 with any
WAVECREST measurement instrument. Please refer to
the VISI User’s Guide for detailed definitions and instructions of this and other VISI tools.
Test System Requirements
To use the OE-2, a complete test system consisting of the following components is needed:
• A
WAVECREST OE-2
• A WAVECREST SIA or DTS (PC or Workstation with VISI installed) instrument
• A source of optical signals
• Interconnecting cables
Before attaching any connector to the OE-2, clean all optical connections using
an optical fiber connector cleaner such as the NTT-ME CLETOP.
To prevent damage to the optical-to-electric (O/E) input connector, a build-out connector is
included with the OE-2. The build-out connector can be replaced if it becomes damaged or dirty.
A dirty or scratched O/E input connector can severely degrade the input signal, resulting in
inaccurate measurements.
NOTE: If the O/E input connector is damaged, the instrument must be returned to
WAVECREST
for repair.
Before Using the OE-2
To ensure the highest accuracy and proper GPIB operation, it is important that:
 All OE-2’s are warmed up for at least ½ hour prior to taking a measurement.
 All OE-2 GPIB addresses have been correctly assigned (see page 8).
 An external calibration of the OE-2 is performed at least once each day (see page 12).
The OE-2 should also be recalibrated if there has been a change of more than 5 C° in
ambient temperature.
Instrument Setup
 Attach the power cord to the back of the instrument and to an appropriate power source.
See Appendix A for specific power requirements.
 Attach the cleaned build-out connector to the OE-2 input.
 Attach the cleaned input signal cable to the build-out connector.
 Turn on main power on the back of the unit.
 Turn on front power switch. The front switch is typically used for daily operations and
also allows easy access to power if the unit is mounted in a rack.
Section 3 | Setup and Measurement | 9

VISI SOFTWARE SETUP
Controller Mode
Edit | Configuration Menu
In order for the OE-2 to communicate with the SIA-3000™ using the GPIB bus, the SIA-
3000 must be in the “Controller” mode. To select Controller mode:
 Select Edit Configuration on the
(pull-down) Menu Bar
 Select OE-2 in the Target
Device pull-down Menu
 Select Controller in the GPIB
Board Mode pull-down menu.
 Click “Apply”
 Click “Close”
Optical Configuration
The Optical Configuration menu enables the user to:
• Set up the IEEE-488 (GPIB) addresses for one or more OE-2’s (up to five OE-2’s can
be addressed in a single VISI-based system).
• Assign each OE-2 channel to a WAVECREST SIA or DTS instrument channel.
• Set preliminary optical measurement parameters.
To access the Optical Configuration menu in VISI, select Edit|Optical Configuration on the (pull-
down) Menu Bar (see figure below).
| Section 3 | Setup Measurement
10

Manually Assigning GPIB Addresses
The GPIB Address Assignment window will appear (see figure below). The fields in this dialog
box will be blank unless device assignments were previously made. The GPIB Address
Assignments dialog box manages the address settings for both the GPIB host and all OE-2’s.
Optical Configuration Dialog Box – GPIB Address Assignment
The Optical GPIB Board field controls the host GPIB address, that is, the GPIB address of the SIA
controller or host controller computer. In most installations, this will be set to 0. In cases where a
host computer has more than one GPIB interface bus connected to it, the Optical GPIB Board
address should be set to the card address for the bus connected to the OE-2’s.
The Optical GPIB Device field sets the address of the OE-2’s connected to the GPIB bus. Set
the Optical GPIB Device to the DIP switch setting on the back panel of the OE-2 and select the
Add Device button. The OE-2 address will appear in the Remote Device List. In the case of
multiple OE-2 installations, each remote device will have to be individually added.
The default address for the OE-2 is 6.
The Device Name (UNIX Only) field is not used at this time.
Automatically Assigning GPIB Addresses
To automatically assign GPIB addresses, click on the “OE Device Search” button to have VISI
automatically search the GPIB network and identify all connected OE-2’s. In addition, clicking
on this button will bring up a pop-up box that asks if existing configurations are to be deleted.
Select the appropriate response.
Section 3 | Setup and Measurement | 11

When all OE-2’s connected to the system are addressed, the next step is to poll the GPIB bus to
see that each OE-2 is correctly addressed. This is done with the Optical Channel Assignment
dialog box. Clicking on the Optical Channel Assignment tab will initiate the polling process.
Each correctly addressed OE-2 will be shown in the Optical Input window along with its GPIB
device address.
If a connected OE-2 does not appear in the dialog box, its address may be incorrectly set.
Return to the GPIB Address Assignments window to correct the address settings.
Dual-channel OE-2’s will occupy two lines in the Optical Input window - one for each optical-
to-electrical channel path in the OE-2. The left-hand OE-2 channel will be named “Port 1” and
the right-hand channel will be named “Port 2.”
Optical Configuration Dialog Box - Optical Channel Assignments
Finally, it is necessary to assign each OE-2 channel to a channel of the WAVECREST DTS or
SIA instrument by highlighting one line in the Optical Input field (corresponding to one channel
path) and selecting the DTS or SIA input channel in the SIA Channel field. To activate this
channel, click the “Active” box.
For example, if you have an optical signal connected to the left hand input port of the OE-2, and
the electrical output of this same channel connected to the channel 3 input on a WAVECREST
SIA-3000, the Optical Channel Assignment should read:
OE-2, GPIB Device 6, Port 1 3 Active
Channel Ports left in the inactive state will still pass signals, but VISI software will not recognize
the channel port.
| Section 3 | Setup Measurement
12